Recent developments in healthcare law support primary care-based intervention to prevent substance use disorder (SUD) and related behavior problems. However, evidence-based programs designed specifically for healthcare settings are lacking. This proposal is to test the effectiveness of integrating and adapting two NIDA- funded procedures for use in primary care pediatric clinics serving low-income youth: 1) the Urgency Indicator (UI) - a nurse-administered screening tool for high risk of substance use (SU) prior to high school and thus also for SUD and 2) the Family Check-Up (FCU) - a brief, family-based program to prevent SU/SUD with replicated efficacy. Recent American Academy of Pediatrics policy calls for this type of approach for preventing SU/SUD and outlines six barriers that have precluded a screening and referral-to-treatment approach for SU prevention in primary care. The UI/FCU integrated program addresses all six barriers. The UI/FCU approach has been rated in preliminary research during well-child check-ups with enthusiasm by youth patients, their parents and their physicians. The UI and FCU are currently being used in ongoing, albeit parallel, studies with the pediatrician collaborators of this proposal, but they have yet to be integrated within the same project. The following three aims focus on evaluating and refining the adaptation of the UI/FCU program for primary-care use: 1) to replicate the effectiveness of the UI screening tool in terms of concurrent and predictive validity and the engagement rate in the FCU; 2) to identify and address challenges in implementing and integrating the UI/FCU prevention strategy within a primary care clinic serving urban, low-income youth; and 3) to test the effectiveness of the UI/FCU on emerging SU, sexual activity, and conduct problems, as well as the putative mediators of these outcomes including parenting and parental well-being. Based on prior FCU efficacy studies, 500 dyads of parents and their 10- to 13-year-old children from low-income, ethnically diverse families will be recruited from a large primary care clinic in an urban community. This sample affords statistical power for effectiveness testing even in subgroups (e.g., age, gender, and race). The FCU will be delivered for two or three years to test impact of dosage. Participants will be followed-up one year after completing FCU to evaluate longitudinal outcomes of the integrated UI/FCU. In addition to traditional effectiveness estimates, analyses will test for mediators and moderators of UI/FCU outcomes as well as whether pre-intervention within-person variability in risk factors (in addition to baseline scores) forecast outcomes. This approach represents a critical step toward a transformational advance in SU/SUD prevention by delivering intervention from pediatric primary care which meets a need identified by that profession, offers fiscal self-sustainability, provides infrastructure for dissemination, ascertains multiple informants (child and parent) for yearly patient monitoring, and serves as a venue for individualized intervention.